宁芜南门头铜矿碳、氧、硫、铅同位素地球化学特征及其地质意义  

Geochemical Characteristics and Geological Significance of Carbon,Oxygen,Sulfur and Lead Isotopes of the Nanmentou Copper Deposit in the Ningwu Area,East China

作　　者：周小栋[1,2] 宋世明[1] 郭坤一[1] 陈国光[1] 陈丹丹[1] 龚娜[1] 曾勇[1] 

机构地区：[1]南京地质矿产研究所,南京210016 [2]福建省地质调查研究院,福州350013

出　　处：《矿物岩石地球化学通报》2015年第5期960-967,共8页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国地质调查局地质调查项目(12120114037901;1212011120854)

摘　　要：为探讨南门头铜矿成矿流体和成矿物质来源,对该矿床的碳、氧、硫和铅同位素进行了研究。结果显示,矿床碳同位素变化不大,为-1.03‰^-0.46‰,氧同位素有两个范围11.40‰~11.80‰和13.50‰~14.00‰,反映成矿流体主要来自深部花岗岩,有部分海相碳酸盐岩地层碳、氧的加入;矿石和花岗岩硫同位素相似,均为较高正值,说明硫主要来源于花岗岩,但有膏盐地层硫的加入;矿石和花岗岩的208Pb/204Pb、207Pb/204Pb、206Pb/204Pb值分别为38.2336~38.4147、15.5618~15.5887、18.1242~18.2936;38.8794~39.5243、15.6194~15.6973、18.7224~19.1461,结合前人Sr、Nd、Hf和Pb同位素特征,说明花岗岩为幔源岩浆上升侵位过程中受到了地壳物质较强的混染形成的,矿石铅来源主要与中生代岩浆岩有关,尚无法排除地层提供部分铅的可能。This paper systematically analyzed C-O-S-Pb isotopes in ores from the Nanmentou Cu deposit to reveal sources of the ore-forming fluid and material. The results show that C isotope values varied slightly from-1. 03‰ to-0. 46‰ and O isotope values fell in two ranges of 13. 50‰ ~ 14. 00‰ and 11. 40‰- 11. 80‰,indicating that the ore-forming fluid might be derived mainly from the deep granite and mixed with carbonate rocks since of water-rock reactions between oreforming fluids and wall rocks. The S isotope values were positively high in both ore and deep granite. The study suggested that S in the deposit mainly came from the granite with mixture from the gypsiferous salt bed. The208 Pb /204 Pb,207Pb /204 Pb and206Pb /204 Pb values changed from 38. 2336 to 38. 4147,from 15. 5618 to 15. 5887 and from 18. 1242 to 18. 2936 in the ore,and from 38. 8794 to 39. 5243,from 15. 6194 to 15. 6973 and from 18. 7224 to 19. 1461 in the granite. In combination of previous studies on Sr,Nd,Hf and Pb isotopes,we suggested that the granite originated from mantle magma invading with mixing from the crust. The source of Pb in the ore were mainly related to the Mesozoic magma but a part of Pb might be from the sedimentary strata.

关 键 词：矿床成因 同位素地球化学 成矿物质来源 南门头铜矿 宁芜 

分 类 号：P597[天文地球—地球化学]